Such auxiliary assemblies can, for example, be water pumps, water circulating pumps, vacuum pumps, compressed-air pumps, lubricant pumps, air-conditioning compressors or also actuators for headlights, locking systems, throttle valves etc. As auxiliary assembly electric motors, use is made of so-called “canned motors” because of their resistance to wear and the hermetic separability of the motor rotor and the motor stator, wherein the canned motors (corresponding to their inherent principle) comprise an electronic commutation, i.e., are designed as so-called brushless electric motors. For the commutation of the stator coils, the electric motor comprises a control electronics system which, in relation to the separating can, is arranged on the closed side in an electronics chamber.
DE 196 46 617 A describes an electric coolant pump wherein the electronics chamber is arranged in a separate casing. Even though the control electronics system is well-protected against the wet area in which the motor rotor is arranged, humidity may still happen to intrude into the electronics chamber also from the pump surroundings and influence or damage the control electronics system. Since air is enclosed in the electronics chamber, it is required, for pressure equalization, to provide a corresponding pressure equalization element which may again cause intrusion of humidity therethrough.
DE 10 2006 033 175 A1 describes a control electronics system to control an electric motor which is entirely encapsulated in a casting compound so that the control electronics system is sealed in a liquid-tight manner against the intrusion of humidity. Before the control electronics system is installed in a motor casing, it has thus already been encapsulated in a casting compound. For this purpose, the control electronics system must first be placed in a cast casing which is then filled with a casting compound. The cast casing must be removed after the casting compound has been cured.